1. Field of the Invention
This invention relates to a method of processing green tea leaves. More particularly, the present invention relates to a method of processing green tea leaves to produce Black Tea that can be brewed in cold water. The method is also designed to produce tea that can be brewed in cold water and of a suitable size and grade for use within a tea bag. The method also is designed to produce high polyphenol Black Tea that can be brewed in cold water or conventional hot tea of any suitable size and grade.
2. Description of the Background Art
Tea is the most widely consumed beverage in the world. Most tea beverages are brewed from black tea. Black tea is manufactured by processing plucked green tea leaves. This process typically includes withering, maceration, fermention, and drying operations. The manufacturing process results in black tea particles of varying sizes, which are sieved into grades according to their sizes and market requirement. Tea of various grades and sources are blended to get required taste and packed bulk in Tea Bag.
The manufacturing process, however, results in a marked reduction in the content of water solubles within the tea leaves. The reduction, in turn, results in part of the green leaf soluble components becoming insoluble. It is believed that the insoluble components are the result of polymeric substances formed by enzyme oxidation occurring during the fermentation step. More specifically, during fermentation, colorless green leaf polyphenols (or catechins) undergo endogenous enzyme mediated oxidation to produce colored polyphenols called Theaflavins (TFs) and Thearubigins (TRs). These colored polyphenols are responsible for the colors characteristic to black tea and its liquor. The insolubles created during fermentation can be either cold or hot water insoluble. In addition to the insoluble components, there are many compounds present in black tea that are only sparingly soluble in cold water. Many of these partially cold water soluble compounds give tea beverages their unique organoleptical properties. As a result of these insoluble and partially soluble components, when traditional black leaves are brewed in cold water the result is a beverage weak in both color and taste
For the reasons stated above, traditionally black teas are usually brewed in hot or boiling water. Namely, the required amount of tea, either loose or in tea bag form, is brewed in boiling water for 2 or 3 minutes, strained and used as a hot beverage. This avoids the problem of cold water insoluble components and also generates a tea beverage of acceptable color and taste.
However, in some regions of the world, especially on the American continent, tea is best enjoyed as a cold beverage, namely iced tea. For example, the hot brewed tea can be refrigerated to achieve an acceptable temperature. Alternatively ice can be added to the hot brewed tea prior to consumption. Yet, both of these options add another step to the process, requiring a substantial amount of additional time.
Another alternative is to brew the tea in cold water for an extended period of time. Yet even with extended brewing times, this option fails to produce a tea with an acceptable strength or color. For this reason conventionally manufactured tea cannot be used for brewing in cold water and similar applications. Still yet another alternative is to use cold water soluble instant tea. These teas typically come in a powder form. Thus, the resulting tea beverage is not brewed, rather it is created by the addition of water. Consequently, these instant teas produce a beverage lacking in flavor and taste, and require the use of additives such as flavor enhancers and or sweeteners. eg. Ready to drink (RTD) beverage or Dry mix.
Over the years attempts have been made to overcome the aforementioned problems and create a tea with improved brewing characteristics. An example of this is presented in Great Britain Patent 1,428,394 to Pendlington. Pendlington provides a process for the preparation of a composite tea product comprising black leaf tea and hot water soluble solids of fermented tea.
Furthermore, U.S. Pat. No. 4,051,264 to Sanderson et al. discloses a process for obtaining a cold water extractable tea leaf. The process involves treating fresh green tea leaves with an enzyme tannase additive to produce dry tea leaves which are cold water extractable.
Both U.S. Pat. No. 6,235,323 to Carns et al, and European Patent Application 910,956 to Carns, disclose a tea bag for iced tea beverages. The tea bag contains a tea mixture of about 30% to about 95% by weight of tea leaves, and about 5% to about 70% by weight of dried soluble tea solids. The resulting bag can be immersed in cold water to provide a tea beverage.
Finally, U.S. Pat. No. 5,863,581 to Barrett discloses a tea manufacturing processes wherein Zeolites are added to green leaf tea and tea powder to improve color properties and speed of color generation. The processes disclose addition of Zeolites prior to extraction and deleafing steps.
Although each of the above described tea processing methods achieves its individual objective, they all suffer from common problems. For example, many of the methods involve the addition of exogenous materials and or enzymes to achieve the desired brewing characteristics. This requires additional time, expense, and processing steps. Additionally, none of the methods involve formulating cold brewing characteristics separate from the fermentation step; that is, any cold brewing characteristics are developed during normal processing operations, thereby lessening the control over such characteristics. Furthermore, none of the above described methods classifies tea particles for selective processing of only those particles suitable for use within a tea bag.
It is therefore one of the objectives of this invention to provide a method of manufacturing a Black Tea that can be brewed in cold water as bulk tea by adding specially prepared cold water soluble tea extracts during fermentation.
It is also an object of this invention to provide a method of making a Black Tea that can be brewed in cold water wherein only grades suitable for use in tea bags are manufactured.
It is a further object of this invention to achieve tea particle classification during the manufacturing process by way of a system of screens.
Still another object of this invention is to produce a Black Tea that can be brewed in cold water that does not require the use of exogenous materials or enzymes during the manufacturing process.
Still yet another object of this invention is to provide a tea manufacturing process wherein cold brewing characteristics are generated and formed separately and thereafter incorporated into the tea during subsequent processing steps.
It is still yet another object of this invention to provide a tea manufacturing method, which allows normal fermentation of the tea and wherein the addition of an extract solution is carried out during a wet stage such that the extract solution is incorporated into the tea particles by way of absorption.
The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter, which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.